��������

Molecular medicine is now a well-established discipline where complementary molecular techniques are used to identify molecular defects behind human diseases and this knowledge is applied to develop molecular treatments.

The rapid development of molecular medicine techniques and their integration into everyday medical practice makes it difficult to imagine the 21st century biomedical scientists or physicians without, at least, a basic understanding of this subject. In our laboratory we attempt integration of molecular and clinical research to study the mechanisms of human diseases, providing research-led education.

Our laboratory benefits from extensive European collaborations established through large European projects, including the EU Collaboration in Science and Technology Action . We also collaborate with the Nencki Institute, Warsaw, Poland.

Our current laboratory research

P2RX7 Purinoceptor as a therapeutic target for treatment of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is the most common inherited muscle disease, which leads to severe disability and death of young men. Therefore, new therapeutic modalities are urgently needed and abnormalities downstream from the absence of dystrophin are realistic targets, with some advantages over gene replacement (Gorecki DC, 2022).

We have discovered that DMD mutations alter extracellular ATP (eATP) signalling via P2RX7 purinoceptor up-regulation, which activation can trigger death of dystrophic muscle cells. Furthermore, ATP is a “danger signal” and P2RX7 its “danger receptor” activating inflammatory responses, which are prominent in DMD muscles. Therefore, the eATP-P2RX7 axis contributes to DMD pathology by stimulating harmful inflammatory responses (reviewed in Gorecki & Rumney 2023).We have demonstrated, that genetic ablation or pharmacological inhibition of P2RX7 in the mdx mouse model of DMD, produced significant functional attenuation of disese symptoms (Sinadinos et al., 2015; AlKhalidi et al., 2018). Hence, the P2RX7 receptor is an attractive therapeutic target with clinical potential. However, its expression can also have protective role in muscles (Rumney et al., 2022).

Crucially, the purinergic abnormality has been proven to affect dystrophic myoblasts. And we subsequently demonstrated that, contrary to the established belief, myoblast functions are affected by DMD gene mutations  (Gosselin et al., 2022). Moreover, myoblast purinoceptor profiles and calcium signalling differ with their muscle origin (Rog et al., 2023). In addition, DMD mutations present early in development (Mournetas et al., 2021). Our findings challenge the central hypothesis stating, that the DMD pathology results from sarcolemma fragility due to the absence of dystrophin in differentiated myofibres. In fact, DMD is a housekeeping gene expressed in many tissues, and downregulation of its expression occuring across cancers correlates with reduced survival of patients (Alnassar et al., 2023).

Therefore, we are currently investigating the molecular mechanism leading from DMD mutations to the plethora of abnormalities such as cell proliferation, differentiation, energy metabolism, Ca2+ homeostasis and death, contributing to DMD pathology but also important for malignancy.

Understanding how DMD gene cause such a range of abnormalities is vital for developing effective therapies.

Relevant publications:

1. Górecki, D. C. (2022) "Dystrophin immunogenicity and requirement in myogenic cells: Paradigm shift in gene therapy for DMD", Clinical and Translational Medicine
2. Gόrecki, D. C., and Rumney, R. M. H. (2023) "The P2X7 purinoceptor in pathogenesis and treatment of dystrophino- and sarcoglycanopathies", Current Opinion in Pharmacology.
3. Rumney, R. M. H., Róg, J., Chira, N., Kao, A. P., Al-Khalidi, R., and Górecki, D. C. (2022) "P2X7 Purinoceptor Affects Ectopic Calcification of Dystrophic Muscles", Frontiers in Pharmacology
4. Gosselin, M. R. F., Mournetas, V., Borczyk, M., Verma, S., Occhipinti, A., Róg, J., Bozycki, L., Korostynski, M., Robson, S. C., Angione, C., Pinset, C., and Gorecki, D. C. (2022) "Loss of full-length dystrophin expression results in major cell-autonomous abnormalities in proliferating myoblasts", eLife
5. Róg, J., Oksiejuk, A., Górecki, D. C., and Zabłocki, K. (2023) "Primary mouse myoblast metabotropic purinoceptor profiles and calcium signalling differ with their muscle origin and are altered in mdx dystrophinopathy", Scientific Reports
6. Mournetas, V., Massouridès, E., Dupont, JB., Kornobis, E., Polvèche, H., Jarrige, M., Dorval, A. R. L., Gosselin, M. R. F., Manousopoulou, A., Garbis, S. D., Górecki, D. C., and Pinset, C. (2021) "Myogenesis modelled by human pluripotent stem cells: a multi‐omic study of Duchenne myopathy early onset", Journal of Cachexia, Sarcopenia and Muscle
7. Alnassar, N., Borczyk, M., Tsagkogeorga, G., Korostynski, M., Han, N., and Górecki, D. C. (2023) "Downregulation of dystrophin expression occurs across diverse tumors, correlates with the age of onset, staging and reduced survival of patients", Cancers

Role of the dystrophin-associated protein (DAP) complex in the brain

Dystrophin functions as a molecular anchor for a number of proteins, which are collectively known as the dystrophin-associated protein (DAP) complex. These proteins have vital roles in various organs, for instance abnormalities of the DAP complex are implicated in brain formation and function. Our research programme aims to understand the role of DAPs in the brain.

We have shown that the absence of specific dystrophins selectively affects inhibitory and excitatory synapses in the cerebellum and alters expression of P2X7 purinoceptors and pro-inflammatory mediators (Jackson et al., 2022). Moreover, a-dystrobrevin (alpha-DB), a protein contributing to the DAP complex in brain astrocytes, is essential for the formation and functioning of blood-brain barrier (BBB), which plays a key role in maintaining brain functionality. Although mammalian BBB is formed by endothelial cells, its function requires interactions between endotheliocytes and glia. Absence of glial alpha-DB causes abnormalities of BBB and progressive brain oedema (Lien et al, 2012). Furthermore, in recent collaborative studies we showed that alpha-DB is important for maintaining the structure and function of the extracellular matrix and its loss result in arteriopathies (MacGregor Sharp et al., 2021). Moreover, alpha-DB knockout mice present with increased motivation for appetitive reward and have altered cannabinoid receptor 1 expression in the brain (Hawkes et al., 2022).  These findings not only help explaining some of the neuropsychiatric abnormalities found in Duchenne muscular dystrophy but may also have implications for other neurological diseases where blood brain barrier function is impaired, such as stroke, dementia, epilepsy and secondary cancers.

Relevant publications:

1. Jackson, T., Seifi, M., Górecki, D. C., and Swinny, J. D. (2022) "Specific dystrophins selectively associate with inhibitory and excitatory synapses of the mouse cerebellum and their loss alters expression of P2X7 purinoceptors and pro-inflammatory mediators", Cellular and Molecular Neurobiology
2. Sharp, M. M., Cassidy, J., Thornton, T., Lyles, J., Keable, A., Gatherer, M., Yasui, M., Abe, Y., Shibata, S., Weller, R. O., Górecki, D. C., and Carare, R. O. (2021) "The α-dystrobrevins play a key role in maintaining the structure and function of the extracellular matrix–significance for protein elimination failure arteriopathies", Acta Neuropathologica Communications
3. Hawkes, C. A., Heath, C. J., Sharp, M. M., Górecki, D. C., and Carare, R. O. (2022) "α-Dystrobrevin knockout mice have increased motivation for appetitive reward and altered brain cannabinoid receptor 1 expression", Acta Neuropathologica Communications

Recent developments in biomedical sciences radically changed many previously accepted opinions and approaches to the diagnosis and treatment of diseases.